Media captionMariano Rajoy: "The state is not bowing down to blackmail"

Spain's prime minister says he will not give in to "blackmail", amid calls for him to resign over alleged links to a suspect in a payments scandal.

Mariano Rajoy said he would fulfil the mandate given by the Spanish people.

The calls came after a newspaper published text messages he allegedly sent to the suspect, Luis Barcenas, ex-treasurer of his Popular Party (PP).

Meanwhile Mr Barcenas repeated in court allegations that Mr Rajoy received payments from a slush fund.

He said Mr Rajoy secretly received money between 2008 and 2010.

An El Mundo report on Monday said Mr Rajoy had sent text messages of support to Mr Barcenas, who is in custody facing trial for corruption and tax fraud. He denies the allegations.

Mr Rajoy, too, denies any wrongdoing, though he did not deny sending the text messages.

He said they showed his commitment to democracy and to allowing the justice system to do its work without political interference.

On Sunday the leader of the country's main opposition Socialist Party, Alfredo Perez Rubalcaba, called for Mr Rajoy's immediate resignation.

'Serious democracy'

At a news conference, Mr Rajoy said a prime minister could not be expected to spend all day denying every rumour or insinuation made about him.

"The rule of law does not bow to blackmail and the institutions, the administrations of justice, the judicial police and tax administrations have acted and are acting and will continue to act with absolute independence," he said.

"This is a serious democracy... and I will submit myself to investigation."

Image caption
Luis Barcenas has been denied bail pending his trial

A series of newspaper allegations that Mr Rajoy and other top politicians received illicit payments has enraged a country in the depths of recession and record unemployment.

It is claimed that Mr Barcenas ran a PP slush fund that took donations from construction magnates and distributed them to party leaders in cash.

El Mundo said last week that it had delivered documents with Mr Barcenas's original ledger entries to the High Court.

Another Spanish paper, El Pais, published similar documents earlier this year.

El Mundo's most recent report includes a text message Mr Rajoy apparently sent to Mr Barcenas in January this year - when the slush fund allegations broke.

He said: "Luis, I understand. Stay strong. I'll call you tomorrow. A hug."

The paper said the conversations showed Mr Rajoy maintained "direct and permanent contact" from at least May 2011 to March 2013.

Correspondents say it is unlikely that Mr Rajoy will step down given his party's outright parliamentary majority.

Mr Barcenas is being investigated over allegations he stashed up to 48m euros (£41m) in secret Swiss bank accounts. Prosecutors allege that some of the funds stem from illegal party donations or kickbacks.

He and his wife are also suspected of falsifying documents on their tax statements between 2002 and 2006.